Extreme selectivity in the lifthyphen;off of epitaxial GaAs films

摘要

We have discovered conditions for the selective lifthyphen;off of large area epitaxial AlxGa1minus;xAs films from the substrate wafers on which they were grown. A 500hyphen;Aring;hyphen;thick AlAs release layer is selectivity etched away, leaving behind a highhyphen;quality epilayer and a reusable GaAs substrate. We have measured a selectivity of gsim;107between the release layer and Al0.4Ga0.6As. This process relies upon the creation of a favorable geometry for the outdiffusion of dissolved H2gas from the etching zone.